The invention relates to a method for separating off organosilicon compounds from wastewater containing organosilicon compounds.
In hydrolysis processes using silanes, as in siloxane production, wastewaters containing organosilicon compounds are produced. The organosilicon compounds contained in the water are not biodegradable and cause what is termed persistent COD (chemical oxygen demand). Persistent COD in wastewater must be avoided for environmental protection reasons.
Ozonolysis is a known method for the degradation of persistent COD from wastewater, but has high operating costs and leads to loss of the organosilicon compounds. The adsorption of organosilicon compounds to silica gel is likewise known, but regeneration thereof is not possible. Therefore, here also high costs arise and the organosilicon compounds are lost.
In DE 113478, DE 2436080 and DE 2804968, methods and devices are described by which liquid/liquid phases can be separated. Using the phase separation elements described, only the droplets of the organosilicon compounds can be separated off from the wastewater. The important fraction of organosilicon compounds dissolved in wastewater cannot be separated in this manner.